1. Field of the Invention
The present invention relates to a technical field of a structure of a reflector-side liquid crystal panel substrate that constitutes a reflective liquid crystal panel; a liquid-crystal panel configured using the liquid crystal panel substrate; electronic equipment configured using the liquid crystal panel; and a manufacturing method for the liquid crystal panel substrate.
2. Description of Related Art
Recently, liquid-crystal panels are used as information display devices of portable apparatuses, such as portable telephones and portable information terminals. Contents of information displayed have been changed from characters and the like to a large amount of information displayed at a time. Therefore, liquid-crystal panels of a dot-matrix type are now used, and the number of pixels is proportionally increasing, thereby requiring higher duty. For these portable apparatuses, a passive-matrix liquid-crystal panel has been used. In the passive-matrix liquid-crystal panel, however, when multiplex driving is performed, selecting signals over line-scanning lines turn to be at a high duty, and a proportionally high voltage is required. This arises problems for battery-driven portable devices for which reduction in power consumption is increasingly demanded.
Under these circumstances, with Japanese Patent Application No. 10-211293, the applicant for the patent has proposed a statically-driven reflective liquid crystal panel that uses a liquid crystal panel made of a semiconductor substrate on which a memory circuit is arranged for each pixel so that display and control are performed according to data preserved in the memory circuit. This reflective liquid crystal panel does not require backlights as a light source because display is shown using light from outside reflecting, thereby allowing reduction in power consumption and allowing to be thin and light.
The reflective liquid crystal panel and the electronic equipment using the panel have well-balanced characteristics required for a display such as that contrast is high, response speeds are relatively high, driving voltage is low, and gray scale display can be easily performed. On the other hand, however, problems still remain unsolved in areas such as that theoretical viewing angles are ranged narrow, and the panel is not as yet suitable to presentation of sufficiently bright displays.
The present invention is proposed in view of the above problems. Accordingly, an object of the invention is to provide a reflective liquid crystal panel substrate that is capable of realizing high-quality reflective displays that provide a wide range of viewing angles and high brightness, a liquid crystal panel using the liquid crystal panel substrate, electronic equipment using the liquid crystal panel, and a manufacturing method for the liquid crystal panel substrate.
In order to solve the above described problems, a liquid crystal panel of the present invention may include, on a substrate, transistors, a light-shielding film connected to the transistors, reflectors connected to the light-shielding film, and a concave-convex film formed in a concave-convex condition and overlaid in regions corresponding to the reflectors via interlayer insulation films under the reflectors.
According to the liquid crystal panel substrate, corresponding to the concave-convex condition of the concave-convex film, surfaces of the reflectors (i.e., reflective surfaces) formed thereabove via the interlayer insulation films are also formed in a concave-convex condition. By this, corresponding to the level of the concave-convex condition, the scattering rate of reflecting light can be increased. As a result, with a reflective liquid crystal apparatus of a direct-view type which is formed using the reflective liquid crystal panel substrate, bright reflection display of high quality on a natural base screen having wide viewing angles can be presented according to reflectors having the most suitable reflecting characteristics that are capable of increasing the luminous intensity of light scattering in a direction perpendicular to a display screen for light that will be incident on at any angle.
In a first mode of the liquid crystal panel substrate of the present invention, as viewed in a direction perpendicular to the substrate, the light-shielding film shields light for gaps between the reflectors, and is formed of the film identical to the concave-convex film.
According to this mode, the concave-convex film is formed of, for example, an A1 film, and a light-shielding film identical thereto for shielding light for the gaps between the reflectors is formed. Therefore, with transistors arranged under the reflectors and the concave-convex film, the light-shielding film shields light which will be incident via the gaps between the reflectors, thereby allowing prevention from a condition where the abovementioned light intrudes into semiconductor layers constituting the transistors to cause light leakage. Also, by forming both the concave-convex film and the light-shielding film from the same film, an unnecessary increase in the number of layers required for the overlay structure can be avoided, thereby allowing simplification in configuration and manufacturing processing for the liquid crystal panel substrate. For reference, even with a transparent concave-convex film, as long as it is formed in a concave-convex condition, since it maintains a basic function of providing a concave-convex condition to the reflectors, advantages in increasing the scattering rate of reflecting light according to the reflectors of the present invention can be obtained.
In another mode of the liquid crystal panel substrate of the present invention, the described conductive film is formed of a first conductive film, and wiring formed of the same film as the first conductive film are provided.
According to this mode, the described concave-convex film is formed of, for example, a film such as the A1 film, and, for example, wiring such as interchange wiring for connecting the reflectors and transistors are formed of the first conductive film. That is, by forming both the concave-convex film and the wiring from the same film, an unnecessary increase in the number of layers required for the overlay structure can be avoided, thereby allowing simplification in configuration and manufacturing processing for the liquid crystal panel substrate. For reference, even with a transparent concave-convex film, as long as it is formed in a concave-convex condition, since it maintains a basic function of providing a concave-convex condition to the reflectors, advantages in increasing the scattering rate of reflecting light according to the reflectors of the present invention can be obtained.
In this mode, a configuration may be such that a different conductive film is further overlaid between the first conductive film and the substrate, wherein indented portions are created on the described concave-convex film formed of a portion of the first conductive film positioned above the different conductive film depending on existence of the different conductive film.
According to this configuration, compared to, for example, the case of a concave-convex film having through-holes simply formed on a planar film as concave sections, in which only two levels occur on a surface thereof; depending on existence of the different film positioned under the concave-convex film, three or more levels can occur on a surface of the concave-convex film. This allows an increase in the scattering rate of reflecting light. In this case, for the different conductive film, patterning may be positively performed so that small indented portions are created over the entire surface of the concave-convex film. Alternatively, patterns such as those of wiring formed of the different conductive film may be used as they are so that indented portions are created.
In another mode of the liquid crystal panel substrate of the present invention, the concave-convex film is formed in the concave-convex condition in a manner that a large number of very small openings are irregularly formed on a planar film.
In this mode, when the openings are formed by etching, the concave-convex film can be formed after the planar film is formed. Therefore, the concave-convex film can be formed in a relatively easy manner. Particularly, to form the wiring and the light-shielding film from the film identical to the described conductive film, the openings can be formed in the same stage as for patterning the wiring and the light-shielding film by photolithographic processing and etching. This produces advantages in simplification of manufacturing processing.
Instead of the openings, the above configuration allows forming of very small protruded sections, thereby forming concave-convex sections, that is, forming convex sections, not the concave sections, so as to form a concave-convex sections. In this case as well, to form the wiring and the light-shielding film from the film identical to the described conductive film, the openings can be formed in the same stage as for patterning the wiring and the light-shielding film by photolithographic processing and etching. This produces advantages in simplification of manufacturing processing.
In another mode of the liquid crystal panel substrate of the present invention, the substrate may be made of a semiconductor substrate.
According to this mode, transistors for switching and controlling the reflectors may be formed on the substrate.
In this mode, the substrate may be formed of a monocrystal silicon material.
In another mode of the liquid crystal panel substrate of the present invention, the substrate is made of a transparent substrate.
According to this mode, the concave-convex film overlaid via a SOG film can be used so as to form surfaces of the reflectors to be in a concave-convex condition, and also, transistors can be formed on the SOG film by use of a SOG technique.
In this mode, the substrate may be formed of glass.
In another mode of the liquid crystal panel substrate of the present invention, the interlayer insulation films include a SOG (silicon on glass) film.
According to this mode, the concave-convex film overlaid via a SOG film can be used so as to form surfaces of the reflectors to be in a concave-convex condition, and also, transistors can be formed on the SOG film by use of a SOG technique.
In this mode, the abovementioned SOG film is subjected to etchback processing.
When the SOG film is subjected to etchback processing, even better reflection characteristics can be provided to the reflectors formed thereabove.
In order to solve the problems described above, the liquid crystal panel of the described present invention may have the liquid crystal sandwiched between the liquid crystal panel substrate and a transparent opposed substrate.
According to the liquid crystal panel of the present invention, since the liquid crystal panel substrate of the described invention is included, with a reflective liquid crystal apparatus of a direct view type formed using the liquid crystal panel, bright reflection display of high quality on a natural base screen having wide viewing angles can be presented according to the reflectors having the most suitable reflection characteristics.
In order to solve the problems described above, the electronic equipment according to the present invention include the liquid crystal panel according to the described invention.
According to the electronic equipment of the present invention, since the liquid crystal panel of the invention is included, according to a reflective liquid crystal apparatus of a direct view type formed using the liquid crystal panel, bright reflection display of high quality on a natural base screen having wide viewing angles can be presented.
In order to solve the above-described problems, a manufacturing method for the liquid crystal panel substrate of the present invention which has multiple scanning lines and data lines, transistors connected to the scanning lines and the data lines, and reflectors connected to the transistors on a substrate may include a step for forming a concave-convex film in a concave-convex condition in regions that will correspond to the reflectors on the substrate, and a step for forming the reflectors via interlayer insulation films on the substrate.
According to this manufacturing method for the liquid crystal panel substrate of the present invention, the concave-convex film in the concave-convex condition is first formed in the regions that will correspond to the reflectors on the substrate. By forming very small openings by etching after the planar film is formed, for example, this step can be performed in a relatively easy manner. Subsequently, the reflectors are formed on the concave-convex film via the interlayer insulation films. Accordingly, the liquid crystal panel substrate of the described invention can be manufactured in a relatively easy manner and with high reproducibility.
The liquid crystal panel substrate of the present invention may include multiple line-scanning lines and multiple column-scanning lines that intersect with each other, multiple data lines arranged the column-scanning lines, voltage signal lines for feeding voltage signals, and multiple pixel-driving circuits arranged corresponding to intersections of the line-scanning lines and the column-scanning lines on a substrate; wherein the pixel-driving circuits have pixel electrodes, switching circuits that turn to be conductive when the line-scanning lines are selected and turn to be nonconductive when at least one of the line-scanning lines and the column-scanning lines is not selected, memory circuits for receiving data signals from the data lines when the switching circuits are conductive and for preserving the data signals when the switching circuits are nonconductive, pixel drivers for outputting first voltage signals from the voltage signal lines to the pixel electrodes when the data signals preserved in the memory circuits are at a first level and for outputting second voltage signals from the voltage signal lines to the pixel electrodes when the data signals preserved in the memory circuits are at a second level, the pixel drivers being connected to reflectors via a light-shielding film, and a concave-convex film overlaid in regions corresponding to the light-shielding film via interlayer insulation films under the reflectors, and formed of the film identical to the light-shielding film formed in a concave-convex condition.
According to the configuration of the present invention, since the reflectors are connected to the pixel drivers via the light-shielding film, the reflectors can be provided to shield light so that the pixel drivers do not cause light leakage that may occur in a condition where light that is incident intrudes into pixel drivers in a region corresponding to the gap between the reflectors. In addition, the concave-convex film is formed of the same film as the light-shielding film in the region corresponding to the reflectors, and corresponding to the concave-convex condition of the concave-convex film, surfaces of the reflectors (i.e., reflective surfaces) formed thereabove via the interlayer insulation films are also formed in a concave-convex condition. By this, corresponding to the level of the concave-convex condition, the scattering rate of reflecting light can be increased. As a result, with a reflective liquid crystal apparatus of a direct-view type which is formed using the reflective liquid crystal panel substrate, bright reflection display of high quality on a natural base screen having wide viewing angles can be presented according to reflectors having the most suitable reflecting characteristics that are capable of increasing the luminous intensity of light scattering in a direction perpendicular to a display screen for light that will be incident on at any angle.
These operational effects and other features and advantages of the present invention will become apparent from the following description of the preferred embodiments.